The pursuit of optimal performance of spark ignition internal combustion (IC) engines typically found in present-day automobiles has been profoundly intensified to increase performance and efficiency while decreasing undesirable exhaust emissions. The original equipment manufacturers (OEM) in the automotive industry are critically invested in the IC engine and have developed an infrastructure of resources and research activities that are not easily replaceable. Also, the performance and drivability of these automobiles are well indoctrinated and accepted by consumers worldwide. Finally, the economy throughout the industrialized world is largely dependent on fossil fuel for powering not only passenger vehicles but also commercial vehicles for trade and travel.
Accordingly, OEMs have, especially in the last twenty years, diligently pursued research activities to develop systems and processes to improve vehicle performance in both torque and efficiency, and to ameliorate the ecological impact of emissions. Advances in performance include turbo and superchargers, fuel direct injection systems, multi-valve intake and exhaust porting for each cylinder, computer control management of the combustion cycle, advanced transmission and catalytic converters for removing undesirable emissions from the exhaust gasses. These efforts have introduced automobiles on the highways with much improved performance, greater fuel efficiencies, electronics control systems that monitor and adjust the critical parameters of the vehicle in real-time and cleaner exhaust emissions that are becoming more acceptable to the environment.
Nevertheless, despite these advances to date, there are increasing burdens on OEMs to further improve vehicular performance, increase fuel efficiency and reduce emissions. Ecological limitations dictate a substantially reduced level of emissions that must be achieved in the immediate future and the cost of fuel has become a significant factor in the overall operating expense of the vehicle. The OEMs must rely on their resources and expertise yet again to meet these demanding challenges. The IC engine is at the center of these challenges and accordingly is receiving top priority by all OEMs.
A major effort is focused on the upgrading of IC engine performance through the improvement of the quality of air/fuel mixture, pre-ignition mitigation via producing a homogeneous and well-dispersed mixture within the cylinder and the advanced control of both valve timing and percentage of valve port opening. These new qualities have been the basis of ever expanding combustion design strategies. There are dogmas in the combustion process which, when adhered to, can produce a performance substantially higher and with less emission than today's vehicles.
In terms of torque and efficiency, the optimization of volumetric efficiency at all engine speeds maximizes the torque delivered; timing of the porting of the inlet valve enhances the homogeneity of the air/fuel mixture for more complete combustion for optimal power, and a cleaner more complete burn producing lower levels of emissions. The ultimate goal is to achieve a stoichiometric charge that theoretically provides maximum efficiency and emission containing harmful by-products. These and other strategies are being investigated with the expectations that new systems will evolve that can contribute to more efficient performance with minimized levels of emissions.
It is well documented and established that infinitely variable valve actuation provides the ultimate opportunity to maximize engine performance and lower emissions. Valving control at all engine speeds and with a stoichiometric charge on demand is a formidable challenge and has the imprimatur of a select high performance group of vehicles that have achieved some success in their operation. The conventional vehicle on the road today offers a fixed cam configuration providing the same valve timing and valve lift at all engine speeds. For this condition there is no opportunity to vary the port opening to capture the full charge of air to maximize torque at all engine speeds, particularly in the mid to high range. To insure maximum power at these levels, valve lift is designed for high-end engine speeds. As a result, performance through the speed range is compromised delivering less efficient performance at all other engine speeds. Among the combustion strategies that are aligned to maximize the combustion process and address the above issues is a technology that involves infinitely variable valve actuation, which under computer control can vary the timing and valve lift.
It is, therefore, an object of the present invention to provide means that will significantly improve the performance of an IC engine as typically found in an automobile by means that provides essentially infinite control of the valve timing in opening and closing of valves in concert with valve percentage port opening for all engine speeds.
It is another object to provide precise lead and lag angles of the intake and exhaust valves in real time.
It is yet another object that computer control of the means will provide command and control that essentially provides infinite control.
It is also a further object to provide delivery of performance efficiently and effectively over the full spectrum that is repeatable and smooth to enhance the driveability of the vehicle.
It is a further object to provide attributes for a system that is infinitely variable in function and in real time that is simple, robust and economical for the complex functions of varying phase angles and percent of valve opening of valves in concert with the vehicle performance.
It is a further object to provide a total system capable of delivering engine performance throughout a speed spectrum that will substantially exceed those available in present-day vehicles without sacrificing power.
It is also a further object to provide the control and means of producing cylinder de-activization such that a six-cylinder engine can function on two, four or six cylinders.
It is yet a further object to provide enhanced engine performance by providing near stoichiometric charges at all engine speeds providing the ultimate opportunity to near zero emissions.